Microencapsulated fire extinguishing agent sn



g (Q DEFENSIVE PUBLICATION UNITED STATES PATENT OFFICE Published at the request of the applicant or owner in accordance with the Notice of Apr. 11, 1968, S49 0.G. 1221. Identification is by serial number of the application and the heading indicates the number of pages of specification, including claims, and 0! sheets of drawing contained in the application as originally filed. The file of this application is available to the public for inspection; reproduction may be purchased for 30 cents per sheet.

Applications published under the Defensive Publication Program have not been examined as to the merits of alleged invention. The Patent Ofiice makes no assertion as to the novelty or the disclosed subject matter.

PUBLISHED APRIL 22, 1969 861 O.Gr. 1020 Microcapsules are adapted to contain a liquid or foamproducing fire-extinguishing agent and to release such agent when subjected to temperatures in a predetermined range. The microcapsules comprise a liquid fire-extinguishing agent such as carbon tetrachloride contained in a thin, hydrocarbon-impervious envelope which is rupturable by heat and/ or pressure at a predetermined temperature range (e.g., 250-450 F.) so as to release the fire-extinguishing agent in the event of a fire. In one embodiment, the microcapsulcs are comprised of a spherical outer polymeric (e.g., a copolymer of styrene and divinyl be nzcne) casing having enclosed therein water and entrapped air or inert gas such as nitrogen or carbon dioxide. In the preferred embodiment, the microcapsules have a density which is equal to or less than that of gasoline and which are added to fuel storage tanks, the tanks of racing cars, airplanes, etc., in order to provide both a fire-blanket and evaporat on-barrier for said fuel.

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